Air conditioning systems are currently commonplace in homes, office buildings and a variety of vehicles including, for example, automobiles. Over time, the refrigerant included in these systems gets depleted and/or contaminated. As such, in order to maintain the overall efficiency and efficacy of an air conditioning system, the refrigerant included therein may be periodically replaced or recharged.
Portable carts, also known as recover, recycle, recharge (“RRR”) refrigerant service carts or air conditioning service (“ACS”) units, are used in connection with servicing refrigeration circuits, such as the air conditioning unit of a vehicle. The portable machines include hoses coupled to the refrigeration circuit to be serviced. A vacuum pump and compressor operate to recover refrigerant from the vehicle's air conditioning unit, flush the refrigerant, and subsequently recharge the system from a supply of either recovered refrigerant and/or new refrigerant from a refrigerant tank.
Refrigerant vapor entering the ACS unit first passes through a system oil separator or accumulator to remove oil entrained in the refrigerant from the air conditioning system. Next, the refrigerant passes through a filter and dryer unit to remove contaminants and moisture from the recovered refrigerant and then the refrigerant is pressurized by a compressor.
Refrigerant vapor is very hot as it exits the compressor during an AC recovery cycle. In a typical flow path, this hot refrigerant enters a compressor oil separator, which separates any compressor oil entrained in the refrigerant from the compressor pass-through from the refrigerant vapor. The compressor oil is then returned to the compressor, and the refrigerant vapor continues along the flow path into a heat exchanger, which assists within the system oil separator or accumulator found earlier in the path. The compressor oil separator and system heat exchanger are two completely different entities within the standard flow path.
In current ACS units, the accumulator, finned-tube heat exchanger, filter and dryer unit, and compressor oil separator are all mounted to the same aluminum manifold block. This enables efficient routing between the components within the block. This also allows for easy access to specific areas within the flow path for valves and sensory components, such as pressure transducers or high pressure switches.
In present systems, a relatively large manifold block footprint is necessary to physically accommodate the components, particularly the larger components such as the heat exchanger, filter and dryer unit, and compressor oil separator. Additionally, heat is lost by the refrigerant in the compressor oil separator and flow tubes between the compressor, compressor oil separator, and heat exchanger, limiting the amount of heat transferred to the accumulator and reducing the overall efficiency of the recovery unit. What is needed, therefore, is an improved heat exchanger for a refrigerant recovery unit.